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公开(公告)号：US3796859A
公开(公告)日：1974-03-12
申请号：US3796859D
申请日：1971-12-27
Applicant: IBM
Inventor： THOMPSON D
Abstract: A magnetoresistive recording head is employed to both magnetize magnetic ink on a document as well as to read the magnetized ink prior to its loss of magnetism. A strong magnet produces the desired bias field along the easy axis of the ink to magnetically polarize the ink, but such strong field is applied perpendicular to the magnetoresistive sensing element, which strong field serves only to bias that sensing element, not switch it.
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Patent Agency Ranking
公开(公告)号：US3840898A
公开(公告)日：1974-10-08
申请号：US31913172
申请日：1972-12-29
Applicant: IBM
Inventor： BAJOREK C , ROMANKIW L , THOMPSON D
CPC classification number: G11B5/3932 , G11B5/399
Abstract: For high density recording (more than 2000 bits per inch) and magnetic bubble sensing, magnetoresistive heads are being used. To operate them most efficiently, the heads are biased about the most linear range of the R-H plot of the magnetoresistive sensor of the head. Provision is made to have such biasing means be an integral part of the transducer so as to permit one to fabricate miniature sensors.
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3.发明授权
公开(公告)号：US3716781A
公开(公告)日：1973-02-13
申请号：US3716781D
申请日：1971-10-26
Applicant: IBM
Inventor： ALMASI G , KEEFE G , LIN Y , THOMPSON D
CPC classification number: G11B5/3903 , G01R33/09
Abstract: A MAGNETORESISTIVE SENSING DEVICE FOR DETECTION OF MAGNETIC FLUX, COMPRISING A MAGNETORESISTIVE SENSING ELEMENT IN WHICH THE SHAPE ANISOTROPY FIELD IS SUBSTANTIALLY PERPENDICULAR TO THE UNIAXIAL ANISOTROPY FIELD. THE LARGER OF THESE TOW MAGNETIC FIELDS IS IN A DIRECTION WHICH IS SUBSTANTIALLY NORMAL TO THE DIRECTION OF THE SIGNAL FLUX WHICH IS TO BE DETECTED, TO INSURE THAT THE MAGNETIZATION VECTOR OF THE SENSING ELEMENT WILL RETURN TO ITS REST STATE WHEN THE SIGNAL MAGNETIC FLUX IS REMOVED. THE EASY AXIS OF THE SENSING ELEMENT CAN BE EITHER PARALLEL OR NORMAL TO THE SIGNAL MAGNETIC FIELD DIRECTION. CURRENT THROUGH THE SENSING ELEMTN IS PREFERABLY PROVIDED BY A CONSTANT CURRENT SOURCE CONNECTED TO THE ELEMENT. THE DIRECTION OF CURRENT THROUGH THE ELEMENT CAN BE EITHER ALONG THE DIRECTION OF THE QUIESCENT MAGNETIZATION STATE OR PERPENDICULAR TO IT. APPLICATIONS INCLUDE MAGNETIC BUBBLE DOMAIN SENSING AND SENSING OF STORED MAGNETIC SIGNALS ON DISKS OR TAPES.
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公开(公告)号：BR7310254D0
公开(公告)日：1974-08-15
申请号：BR1025473
申请日：1973-12-28
Applicant: IBM
Inventor： THOMPSON D , BAJOREK C , ROMANKIW L
Abstract: 1450204 Magnetic heads INTER. NATIONAL BUSINESS MACHINES CORP 9 Nov 1973 [29 Dec 1972] 52064/73 Heading G5R [Also in Division H3] A magnetic sensing head comprises a unitary structure of a layer of magneto-resistive material 16 for sensing a magnetic field and an adjacent biasing layer 14 of permantly magnetized material to bias the layer 16 magnetically to a required operating range, layers 14 and 16 being in direct contact with one another. The layers 14 and 16 may be co-planar or laminated, with the direction of magnetization, arrow M h , of bias layer 14 parallel or perpendicular to the easy axis and sense current direction, arrow I, of layer 16. Layer 16 is of permalloy material, e.g. Ni-Fe, Ni-Co or Ni-Fe-Co, and the bias layer 14 may be of ferrite. Layers 14,16, may be evaporated, sputtered or electroplated on a substrate 12 with thicknesses of 200 to 2000 and 50 to 400 Šngstroms respectively. The bias may be established due to exchange or epitaxially coupled layers 14, 16, there being direct atomic contact between the layers. In another form the biasing layer 14 is a composite layer comprising exchange or epitaxially coupled films with a magnetically soft film atomically coupled to a magnetically hard film, e.g. Ni-Fe deposited on a Fe 2 O 3 , a Fe 2 O 3 on Ni-Fe, Co or Co-rich Ni-Co on vanadium or chromium, or binary Co-P. In a further form, the bias layer, or two bias layers with the sensing layer therebetween, is or are formed by preferentially oxiding one or both surfaces of a permalloy sensor strip. Alternatively such surfaces may have localized zones with a raised coercivity produced by chemical reaction with chlorides or sulphates, etching to roughen the surfaces, or by selective deposition of materials which exchange couple to the sensing layer. The combined sensing and bias layers may be surrounded by a magnetic shield (8) in a record head, Fig. 1 (not shown). The head may be used for reading tapes, discs, magnetic ink, or sheets capable of generating and transporting magnetic bubble domains.
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公开(公告)号：BR8004063A
公开(公告)日：1981-01-21
申请号：BR8004063
申请日：1980-06-27
Applicant: IBM
Inventor： THOMPSON D
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